"All in all, we believe a post-POG world presents us and other competitors, as a result, with enhanced opportunities and is at worst neutral and at best highly positive, resulting in further consolidation and concentration," the release said.

"Its structure and organization is clunky," he said in a statement. "Potential client and, even more importantly, people conflicts are considerable, exacerbated by a lack of pre-announcement consultation."

WPP charts represented "POG" with what he described as "a sludgy brown color," which Mr. Sorrell gleefully explained was what you get when you mix purple and orange [the corporate colors of Publicis and Omnicom].

WPP said that in response, it will continue to invest in growth areas like new media, data investment management, and rapidly developing markets. The holding company, home to agencies Burson-Marstellar, Ogilvy, and Grey, said it has raised its fast-growth markets and new media sector targets from 35-40% of total revenues to 40-45% each over the next five years.

The company also said it would continue to leverage its "Team" approach, which offers clients brand-specific teams made up of personnel from various WPP agencies.

"Again, a reinforcement of the same strategy, but more and faster, as we have already started to implement," the release said.

WPP slightly raised its 2013 forecast from just more than 3% growth, but did not say what the new target was. The company reported top-line revenue of $8.2 billion, and like-for-like growth of 2.4%.